Thread: Binomial Distribution

Explain whether or not a binomial distribution is a suitable model for the random variable.

(a) the number of tosses of a fair coin before the coin lands 'head'

(b) the score a pupil gets in answering 10 true/false questions with 1 mark for a correct answer and -1 for a wrong answer

(c) the number of rainy days in a randomly chosen week at a certain place for which weather records show that it rains on 40% of the days

Originally Posted by acc100jt

Explain whether or not a binomial distribution is a suitable model for the random variable.

(a) the number of tosses of a fair coin before the coin lands 'head'

(b) the score a pupil gets in answering 10 true/false questions with 1 mark for a correct answer and -1 for a wrong answer

(c) the number of rainy days in a randomly chosen week at a certain place for which weather records show that it rains on 40% of the days

Apply the three criteria for a binomial distribution to each of the given random variables.

(a) No. The number of trials if not fixed.

(b) No. If I let X be the number of questions answered correctly, then X~Bin(10,0.5)
but the marks obtained (Y) is given by Y=(1)X+(-1)(10-X)=2X-10 is NOT a binomial

(c) Maybe....the probability that probability that it rains might not be the same due to seasons.

Am I correct?